Panel-Mounted Current Transducers Operate from Unipolar Supply

LEM’s series of current transducers is designed to operate from a single +5-V power supply. The seven units offer maximum current measurements from 50 A_RMS to 600 A_RMS. The internal reference voltage (2.5 V) is provided on a separate contact (of the Molex 5045-04A connector) or can be forced by an external reference to a value between 2 V and 2.8 V for reference thermal drift cancellation. Gain and offset are fixed and set so that the output voltage is equal to Ref in or Ref out (±0.625 V) for the primary nominal rms current (I_PN).

The transducers can measure dc, ac and pulse currents, with low power consumption, while providing galvanic isolation between the primary and output circuits. The units share the same mechanical design, measuring 1.6 in. x 1.2 in. x 1.3 in. (40 mm x 30 mm x 32.5 mm) with a 0.8-in. x 0.4-in. (20.4-mm x 10.4-mm) aperture for the primary conductor. The transducers weigh 55 g.

A unique LEM ASIC designed for use with open-loop Hall-effect technology has been used to provide performance improvements, including better offset and gain drifts and improved linearity. It also extends the operating temperature range to -40°C to +85°C.